<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <script src="https://unpkg.com/vue@3/dist/vue.global.js"></script>
</head>
<body>
  <div id="Application">
    <h1>{{ count }}</h1>
    <div>{{ type }}</div>
    <button @click="add">add</button>
  </div>

  <script>
    const { createApp, ref, computed } = Vue;
    let config = {
      setup() {
        const count = ref(0)
        const add = () => {
          count.value++
        }
        const type = computed(() => {
          return count.value > 10 ? 'big' : 'small'
        })
        return {count, add, type};
      },
    };
    const app = createApp(config)
    const instance = app.mount("#Application");
    instance.add()
    console.log(instance.count);
  </script>
</body>
</html>